Ovotransferrins conalbumins

Ovotransferrin (conalbumin) Avian egg white Protection (antibacterial, antioxidant)... 

The transferrins are a group of specific metal-binding proteins, the best characterized of which are serotransferrin (present in blood plasma, milk, spinal fluid and semen), ovotransferrin (conalbumin present in avian and reptile egg white) and lactotransferrin (present in milk, pancreatic juice, tears and leucocytes). 

Ovotransferrin (conalbumin), Gal d 3, is a single glycosilated polypeptide with a molecular weight of 76 kDa. The metal (e.g., iron, cupper, zinc)-binding capacity of... 

Ovotransferrin is also obtained from the white portion of a chicken egg and has been used as a chiral selector in liquid chromatography. This protein is also called conalbumin. It is a metal ion (iron, copper, manganese, and zinc) binding protein of molecular mass 70,000-78,000 and with an isoelectric point of 6.1-6.6. This protein is sensitive to acids and heat. 

Aisen, P., A. Leibman, and H. A. Reich Studies on the Binding of Iron to Transferrin and Conalbumin. J. Biol. Chem. 241, 1666 (1966). They have found by electrophoretic studies that the stability constants of the two binding sites in ovotransferrin and human serum transferrin are equivalent. By proton magnetic relaxation rate measurements, they also found that the binding sites of ovotransferrin and human serum transferrin acted independently. 

When ferric iron (preferably as ferric nitrilotriacetate) is added to egg white, with a little salt, and the mixture is shaken, a vivid red color develops. This simple experiment introduces the protein ovotransferrin (formerly known as conalbumin) and the most striking property of transferrins, their ability to rapidly and tightly bind iron. 

The zero field data show the effects of neighboring nuclear magnetic moments (Fig. 14) which are represented by a random magnetic field of about 4 Oersted acting on the electronic moment of the iron. Aasa s experiments (27) on the transferrin of Hagfish show it to be quite different from that of human serum transferrin and distinctly shows the differences in the two iron sites. Conalbumin or ovotransferrin is similar to serum transferrin in that they both form pink complexes with ferric iron with absorption maximum at 465 mm and both bind iron tightly in two different sites. A recent Mossbauer study by Aisen, Lang and... 

In the meantime, in 1947, Laurell and Ingelman[17] had independently purified the red protein from pig plasma and in the same year proposed the name transferrin which has since been adopted as the generic name of the proteins of this family serotransferrin (instead of siderophilin) present in blood and some external secretions, ovotransferrin (instead of conalbumin) in avian egg-white, lactotransferrin (also called lactoferrin) from milk, external secretions and leukocytes and melanotransferrin (instead of p97) in melanocyte and normal cell plasma membrane. A dozen mammalian and some frog, fish and insect serotransferrins were later isolated and characterized. 

Ovotransferrin, also known as ovoconalbumin or conalbumin (76 kDa, pf = 6.1), which in hens is identical with serum transferrin, shows antimicrobial effects. This protein coagulates at a lower temperature than ovalbumin (coagulation temperature is 53 °C) and forms complexes with divalent and trivalent metal ions. Complexes with iron can cause a pink discolouration of products containing egg white. 

Ovotransferrin, or conalbumin, is found in egg white and functions similarly to transferrin. Aisen et al. observed that the two iron-binding sites are different in a Mossbauer spectrum at 4.2 K in an external magnetic field of 550x10 Am (550 Oe). ... 

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